JPWO2013125548A1 - Fluorine resin film - Google Patents

Abstract

To provide a fluororesin film that has a heat ray blocking function and can transparently see a natural color with a transparent feeling without impairing the high transparency, mechanical characteristics, weather resistance, etc. inherent to the fluororesin. Disclosed is a fluororesin film that maintains the properties of a fluororesin film such as mechanical properties, transparency, and long-term weather resistance, is excellent in heat ray shielding properties, is colorless and transparent, and allows natural colors to be seen through. A fluororesin film containing indium tin oxide having an average particle diameter of 10 to 200 nm and a blue pigment having an average particle diameter of 10 to 200 nm, the indium tin oxide content A (% by weight) in the film; A fluororesin film, wherein the blue pigment content B (% by weight) satisfies the following formulas (1) and (2) simultaneously: 10 / t≰A≰60 / t (1) 0.05A≰B≰0.3A (2) In the above formula, t represents the film thickness (μm).

Description

  The present invention relates to a fluororesin film having excellent heat ray blocking properties. More specifically, the present invention relates to a fluororesin film that has excellent heat ray blocking properties and is transparent and colorless and transparent to natural colors.

Technical background

  Fluoropolymer film has excellent weather resistance, transparency, mechanical properties, moisture resistance, agricultural house covering materials, roofing membrane materials, window materials, solar cell surface protection materials, condensing panel surface materials, display plate surface materials, Used for building exterior materials.

  In particular, in the field of building materials such as roofing membrane materials and window materials, daytime indoor lighting is not required due to the introduction of sunlight from the consideration of the environment, and the natural color appearance of indoor exhibits by natural light is provided, and indoors Demand is expanding due to advantages such as the feeling of opening when the sky is visible.

  On the other hand, since sunlight contains ultraviolet light and infrared light (heat rays), it may be harmful. For example, humans can cause dermatitis when exposed to strong ultraviolet rays, and synthetic substances can deteriorate. Indoors where a large amount of infrared rays are inserted can lead to a rise in temperature, which may cause discomfort to the occupants and damage to house-grown plants.

  In order to solve these problems, for example, Patent Document 1 discloses an infrared shielding agricultural sheet in which inorganic fine particles such as tin oxide are dispersed and mixed in a synthetic resin, and Patent Document 2 discloses a metal oxide whose surface is coated with amorphous silica. A fluororesin film containing physical particles, Patent Document 3, discloses a heat ray-shielding fluororesin composite sheet containing infrared-shielding inorganic fine particles on at least one surface and a roofing material using the same.

Patent Document 4 discloses a biaxially oriented polyester film for window pasting that has a near-infrared absorber containing a near-infrared absorber in the intermediate layer and is excellent in transparency, and Patent Document 5 discloses a transparent conductive material that is also an infrared blocking substance including heat rays. A transparent conductive laminate having an improved membrane transmission color is disclosed.
However, since the agricultural sheet of Patent Document 1 contains inorganic particles mainly composed of tin oxide at least 3 parts by weight or 10 parts by weight or more with respect to 100 parts by weight of the synthetic resin, it has an infrared shielding property including heat rays. Since the visible light transmittance is inferior and it appears dark, there is a problem inferior in transparency. In addition, since the base resin is a composite resin selected from polyethylene terephthalate resin, polyvinyl chloride resin, and polyolefin resin, even if an antifouling layer or dew-proof layer is provided on the surface, strength deterioration or fading occurs due to the influence of ultraviolet rays. It was difficult to obtain long-term durability.

  Patent Document 2 is a heat ray shielding fluororesin film in which composite particles having a 95% particle size distribution range of 0.1 to 30 μm are dispersed in a fluororesin. The composite particles used are metal oxide composite particles whose surface is coated with amorphous silica. However, since the particle size is large (average particle size: 0.5 to 10 μm), it is transparent when the addition amount necessary for heat ray blocking is used. As a result, there is a problem that it is difficult to see natural colors when seen through because the color is lowered and the particle color appears.

  Patent Document 3 is a composite sheet in which a fluororesin layer containing near-infrared shielding inorganic particles is provided on at least one side of a reinforcing base material. The reinforcing substrate used is a fiber woven fabric such as a glass fiber woven fabric, a polyamide-based fiber woven fabric, or a polyester-based fiber woven fabric, and the color pattern of the fiber woven fabric appears, resulting in a problem of poor transparency.

  Patent Document 4 has an intermediate layer in which an imonium compound, a phthalocyanine compound, an aluminum compound, a polymethine compound and the like are blended in a polyester resin as a near-infrared absorber in order to control solar radiation transmittance, and visible light transmittance is 70 to 90. %, And a haze of 5.0% or less is proposed as a three-layer coextrusion laminated polyester film. Even in this method, there is a problem that the transmission of light by the near-infrared absorber is inevitably colored, and the visible light transmittance is lowered. A colored film in which a near-infrared absorber and a dye having absorption in the visible light region are added to the intermediate layer has also been proposed, but for the purpose of coloring, the visible light transmittance is further reduced. Further, since the base resin is polyester, it is difficult to obtain long-term weather resistance due to deterioration due to ultraviolet rays.

  In Patent Document 5, a transparent conductive film made of a specific refractive index material and indium tin oxide (hereinafter sometimes referred to as ITO) is laminated in this order on a transparent substrate, so that there is no yellow color as an ITO transmission color. A transparent conductive laminate having a neutral color is disclosed. This method has a problem that the transparent conductive film (ITO) is the outermost layer, which is inferior in outdoor long-term weather resistance, and is inferior in the bending resistance and scratch resistance inherent to the thin film lamination. Furthermore, the transparent conductive film (ITO) formation by the vacuum deposition method, the sputtering method, the CVD method or the like has a problem that the processing is complicated and the cost is high.

JP-A-9-205898 JP 2002-69258 A Japanese Patent Laid-Open No. 2004-25586 JP 2001-171060 A JP 2008-181838 A

The object of the present invention is to solve the above-mentioned problems, while maintaining the properties of a fluororesin film such as mechanical properties, transparency, and long-term weather resistance, it has excellent heat ray blocking properties, is colorless and transparent, and can see through natural colors. It is in providing a heat ray shielding fluororesin film. Moreover, the heat ray blocking property referred to in the present invention is a general term for functionality that reflects or absorbs all or a part of light rays generally classified as infrared rays and does not completely or partially transmit light rays.

In order to achieve the above object, the present invention has the following configuration.
(I) a fluororesin film containing indium tin oxide having an average particle diameter of 10 to 200 nm and a blue pigment having an average particle diameter of 10 to 200 nm, the content of indium tin oxide A (% by weight) and the blue pigment A fluororesin film characterized in that the content B (% by weight) satisfies the following formulas (1) and (2) at the same time with the film thickness t (μm):
10 / t ≦ A ≦ 60 / t (1)
0.05A ≦ B ≦ 0.3A (2)
(Ii) The fluororesin film as described above further satisfying the following formula (A) as light transmittance T _IR (%) at a wavelength of 1800 to 2200 nm.
20 ≦ T _IR ≦ 70 (A)
(Iii) The film thickness t of the fluororesin film is 10 to 500 μm, the yellowness YI of the fluororesin film, the light transmittance T _V (%) at a wavelength of 380 to 700 nm, and the wavelength at 1800 to 2200 nm The fluororesin film having a light transmittance T _IR (%) that simultaneously satisfies the following formulas (3), (4), and (5):
−0.01t ≦ YI ≦ 0.03t (3)
85 ≦ T _V ≦ 98 (4)
20 ≦ T _IR ≦ 50 (5)
(Iv) The fluororesin film as described above, wherein the blue pigment is cobalt blue.

  According to the present invention, the transmittance of harmful rays is controlled without impairing the properties such as transparency, mechanical properties, weather resistance, etc. inherent to the fluororesin film, and there is no yellowing due to the addition of indium tin oxide, colorless transparency And a fluororesin film having excellent heat ray shielding properties at the same time.

A schematic diagram of a heat ray blocking evaluation tester is shown.

  The fluororesin film of the present invention is a film composed of a resin comprising a fluoroolefin homopolymer, a copolymer of two or more fluoroolefins, or a copolymer of one or more fluoroolefins and other monomers.

  The fluoroolefin is a monomer having a polymerizable unsaturated bond and a fluorine atom, and may further have a hydrogen atom, a chlorine atom, an oxygen atom, or the like. Examples of the fluoroolefin include tetrafluoroethylene, vinyl fluoride, vinylidene fluoride, perfluoroalkyl vinyl ether, chlorotrifluoroethylene, and hexafluoropropylene. Other monomers are preferably non-fluorine monomers, olefins such as ethylene, propylene, butene and norbornene, alkenyl ethers such as cyclohexyl methyl vinyl ether, isobutyl vinyl ether, cyclohexyl vinyl ether, ethyl vinyl ether and ethyl allyl ether, vinyl acetate and pivalin. Examples thereof include alkenyl esters such as vinyl acid and allyl pivalate.

  Typical fluororesins include polytetrafluoroethylene (PTFE), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / propylene copolymer, ethylene / tetrafluoroethylene copolymer. (ETFE), tetrafluoroethylene / hexafluoropropylene / ethylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer such as tetrafluoroethylene / perfluoropropyl vinyl ether copolymer (PFA), and polyvinylidene fluoride (PVDF), vinylidene fluoride / hexafluoropropylene copolymer, vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer, polyvinyl fluoride (PVF), polychloro Examples include, but are not limited to, trifluoroethylene (PCTFE), ethylene-chlorotrifluoroethylene copolymer (ECTFE), and mixtures thereof and fluororesins based on these are also included. It is.

  If necessary, a thermoplastic resin not containing fluorine and various additives can be blended within a range that does not impair the properties of the fluororesin. For example, various resins such as olefin-based, acrylic-based, ester-based, and amide-based thermoplastic resins, various pigments (apart from the blue pigment in the present invention), dyes, organic or inorganic fine particles (the present invention) In addition to indium tin oxide, fillers, dispersants and the like can be mentioned.

  When used as a covering material for an agricultural house or a roof membrane material, a resin mainly composed of ETFE, FEP, PVF, and PVDF is preferable from the viewpoint of film forming property, transparency, handleability, cost, etc. Among them, ETFE resin is more preferable. .

  In the present invention, indium tin oxide (ITO) refers to an inorganic compound composed of indium oxide and tin oxide. It is known that it has optical transparency in the visible light region and exhibits conductivity from its charge density. Because of these two characteristics, it is often used mainly as a transparent electrode. For example, it is widely applied in liquid crystal displays, plasma displays, touch panel screens, electronic ink in electronic paper, organic EL electrodes, solar cells, antistatic agents, electromagnetic shielding materials, and the like.

  The ITO powder exhibits yellow to gray. When dispersed in a resin, it has transparency, but when it is exposed to light, it exhibits a slight powder color (yellow to gray).

  In the present invention, ITO is used as fine particles. The production method of the ITO fine particles is not particularly limited. For example, a powder sintering method in which an indium oxide powder and a tin oxide powder are pressure-molded and baked and solidified, and an aqueous solution containing an indium salt and a tin salt is neutralized. Examples include a method of firing the precipitate after filtration, washing, and drying. It is known that pulverization can be carried out industrially and that an average particle size of 100 nm or less can be produced.

  The average particle diameter of the ITO fine particles in the fluororesin film of the present invention is in the range of 10 to 200 nm. If it exceeds 200 nm, there is a decrease in light transmittance and an increase in haze, which is not suitable as a transparent film material from the viewpoint of visibility. If it is less than 10 nm, the heat ray blocking efficiency becomes insufficient.

  Furthermore, the component ratio of indium oxide and tin oxide can be adjusted, and in general, there are many indium oxide: tin oxide = 95: 5 (weight% ratio, hereinafter the same), but 85:15 to 97 : There are various ratios in the range of 3, and can be appropriately selected and used from the viewpoint of achieving both transparency and heat ray blocking properties, but from the viewpoint of content, the effect is less than indium tin oxide of other component ratios. Indium oxide: tin oxide = 97: 3 is more preferable, but considering application to a transparent roof membrane, window material or wall material, a large capacity of indium tin oxide is required. Therefore, indium oxide: tin oxide = 95: 5, which has a stable circulation amount, is preferable.

  In the present invention, the blue pigment is an inorganic or organic compound that exhibits a blue color when exposed to sunlight, and examples thereof include inorganic pigments such as cobalt and manganese, and organic pigments such as indigo, phthalocyanine, and anthraquinone. . Cobalt pigments and phthalocyanine pigments are preferable in terms of color developability and handling when added to a fluororesin, and cobalt pigments are more preferable in terms of yellowish color reduction effect, heat resistance, weather resistance, etc. due to the addition of ITO. Cobalt blue is more preferable.

Cobalt blue is also called cobalt blue, PIGMENT BLUE 28, and the like. The composition formula is represented by CoAl ₂ O ₄ (cobalt aluminate) or CoO · Al ₂ O ₃ (spinel-type crystals of cobalt oxide and aluminum oxide). It excels in light resistance, weather resistance, acid resistance, and alkali resistance, and exhibits very stable color development in the process of adding to the fluororesin and the outdoor exposure of the additive film.

  An organometallic blue pigment called phthalocyanine blue, which is commonly used as a blue pigment, has almost the same yellowing suppression effect as an inorganic pigment, but it can be added to a fluororesin depending on the usage environment from the viewpoint of heat resistance and weather resistance. Cobalt blue having a wider application range is preferable. The average particle diameter of the blue pigment in the fluororesin film of the present invention needs to be in the range of 10 to 200 nm. If the thickness is less than 10 nm, the light scattering property sufficient to be colored blue with respect to the transmitted light (sunlight) to the fluororesin element film cannot be obtained, so that the intended function as a blue pigment can be achieved. Therefore, the effect as the fluororesin film of the present invention is not exhibited. If it exceeds 200 nm, it is not suitable as a transparent film material from the viewpoint of visibility due to a decrease in light transmittance and an increase in haze.

  The method of blending the ITO fine particles and the blue pigment in the fluororesin film is not particularly limited, but a composition in which ITO and the blue pigment are separately dispersed in a fluororesin or the like (hereinafter referred to as ITO master and blue master, respectively) In general, a method is used in which an ITO master and a blue master are mixed in a fluororesin serving as a base at the time of film formation and mixed at a predetermined concentration. There is a method in which ITO fine particles and blue pigment are mixed and dispersed in a fluororesin or the like. However, from the viewpoints of optimization of dispersion conditions, freedom of added concentration, etc., it is preferable to use a separately dispersed master. The shape is preferably in the form of pellets in terms of transportability to the film forming apparatus, etc., and is preferably equal to the pellet size of the base resin of the fluororesin film.

  The resin in which the ITO fine particles or / and the blue pigment are dispersed is preferably the same type as the base resin of the fluororesin film or the above-mentioned fluororesin. From the viewpoints of particle dispersibility, affinity with particles, economy, etc., a resin that does not contain fluorine in the molecular chain can be used, but from the viewpoint of transparency and surface roughness, the base of the fluororesin film What has compatibility with resin is more preferable.

  The dispersion method is not particularly limited, but a method in which ITO fine particles or / and blue pigment particles and resin are melt-kneaded, a method in which ITO fine particles or / and blue pigment dispersion and resin are melt-kneaded and the dispersion medium is removed simultaneously, ITO A method of dispersing the fine particles or / and blue pigment in the resin solution and then removing the solvent is used. In any method, the so-called binder resin before mixing is preferably a powder having a large surface area. For example, the method of melt kneading the ITO fine particles or / and the blue pigment and the resin includes mixing the powdered resin and the particle powder with a tumbler, ribbon blender, nauta mixer, Henschel mixer, planetary mixer, etc. A method of cutting and kneading the extruded strand into a master pellet by using a single or twin screw extruder, or a high-shearing of the pulverized resin and the particle powder using a Banbury mixer, kneader, calender roll, heating kneader, etc. A method is known in which a resin composition that has been primarily kneaded by a kneading apparatus is prepared in advance, and this resin composition is mixed with the same resin or another resin to obtain master pellets in the same manner as described above. A dispersant and various stabilizers can be added as necessary, but it is necessary to select one having heat resistance and chemical resistance that does not decompose at the kneading temperature or film forming temperature.

  The particle concentration in the particle master is preferably a master chip dispersed at a concentration 2 to 100 times the concentration added to the film. The higher the concentration of the master chip, the more advantageous in terms of dispersion processing cost, etc. However, when it is 100 times or more, the master chip may be unevenly distributed when mixed with the base resin, resulting in a non-uniform film.

  The ITO content A (% by weight) of the fluororesin film of the present invention is represented by the following formula (1), and varies depending on the film thickness t (μm). Since the heat ray blocking effect depends on the ITO content per unit area of the film, a thick film is effective at a low concentration.

10 / t ≦ A ≦ 60 / t (1)
When A is smaller than 10 / t, the heat ray blocking efficiency is extremely deteriorated. When A is larger than 60 / t, yellowish coloration peculiar to ITO becomes strong, haze increases, and transparency is extremely lost.

  The blue pigment content B (% by weight) of the fluororesin film of the present invention is represented by the following formula (2) and depends on the ITO content A (% by weight). In order to make the color of the fluororesin film colorless, the blue pigment content is adjusted in accordance with the ITO content. The target reduction in yellowishness can be achieved by bringing the YI value closer to ± 0.

0.05A ≦ B ≦ 0.3A (2)
The ITO content and the blue pigment content in the fluororesin film may be confirmed by atomic absorption (ICP) analysis, or may be determined by weight conversion of ash.

  The particle diameters of the ITO fine particles and the blue pigment in the fluororesin film can be measured by slicing the fluororesin film with a microtome and observing and measuring the sliced cross section with a transmission electron microscope or the like.

The light transmittance T _IR (%) at a wavelength of 1800 to 2200 nm of the fluororesin film of the present invention is preferably T _IR = 0 in view of the relationship with the near-infrared transmittance from the viewpoint of the heat ray blocking effect. In order to achieve both transparency close to natural light, which is the object of the present invention, a range represented by the following formula (A) is preferable.

20 ≦ T _IR ≦ 70 (A)
When the _TIR is 20% or more, when the amount of indium tin oxide necessary for this is added, and when the blue pigment necessary for obtaining transparency close to natural light is added, a visible distance of about 30 meters ahead through the film Therefore, it is preferable that the _TIR is 70% or less, so that the necessary heat ray blocking property can be exhibited.

  The fluororesin film of the present invention may have a single layer configuration, or may be a laminated film including at least one fluororesin film of the present invention. For example, if a pattern-colored film is bonded, design properties can be imparted.

  In film formation, known film formation methods such as melt extrusion film formation, calendar film formation, and solution film formation can be applied, but melt extrusion film formation is preferable from the viewpoints of film thickness control, productivity, additive dispersibility, and the like. The film may be any of unstretched, uniaxially stretched, and biaxially stretched, but a substantially non-oriented unstretched film is preferable from the viewpoints of dimensional stability, transparency, and ease of film formation.

  The film thickness is not limited because it depends on the application, but is preferably 10 to 500 μm, more preferably 20 to 300 μm. If the thickness is less than 10 μm, the waist is weak and the handling property is inferior, and the strength is not sufficient. If it exceeds 500 μm, the transparency is lowered, the weight is increased, and the handling property is inferior.

  The yellowness of the fluororesin film of the present invention is optically colorless when YI = ± 0, but the range represented by the following formula (3) is a preferable range in which transmitted light can be seen as a natural color. On the other hand, when the YI value is lower than the value of the expression (3), a blue color is strongly felt and it is generally difficult to see the transmitted light as a natural color.

−0.01t ≦ YI ≦ 0.03t (3)
In the above formula, t represents the film thickness (μm).

The light transmittance T _V (%) at a wavelength of 380 to 700 nm of the fluororesin film of the present invention is preferably 100% from the viewpoint of transparency, but light absorption by the film is inevitable, and transparency close to natural light is obtained. The range represented by the following formula (4) is preferable for obtaining.

85 ≦ T _V ≦ 98 (4)
If T _V is more than 85%, preferably because of its excellent light transmittance.

The light transmittance T _IR (%) at a wavelength of 1800 to 2200 nm of the fluororesin film of the present invention has a range represented by the following formula (5) in order to achieve transparency close to natural light which is the object of the present invention. Even more preferred.

20 ≦ T _IR ≦ 50 (5)
By setting _TIR to 50% or less, it is possible to further exhibit the heat ray blocking property that is practically required.

  Although the use of the fluororesin film of the present invention is not particularly limited, for example, it can be applied to electronic equipment parts as agricultural house covering materials, roof membrane materials, various window materials, solar cell surface protective materials, and infrared ray shielding films. Application, vehicle ceiling materials.

Hereinafter, although it demonstrates concretely based on an Example, it is not limited to a following example.
Each characteristic was evaluated based on the following measurement method.

(1) Light transmittance T _V (%) at a wavelength of 380 to 700 nm
Using a spectrophotometer U-2001 (manufactured by Hitachi High-Tech Co., Ltd.), the transmittance in the wavelength range of 380 to 700 nm is continuously measured by the double beam direct ratio metering method, and each transmittance value (T _V i) for each wavelength of 1 nm is measured. ) T _v and the ray transmittance _T V (%) the percentage of divided by the number of measurement points (n) the sum of i at wavelength 380 to 700 nm. Further, the light transmittance T _V (%) is sometimes referred to as a visible light transmittance because of its property, and is commonly used in the case of implementation.

(2) Light transmittance T _IR (%) at a wavelength of 1800 to 2200 nm
Using a spectrophotometer U-4100 (manufactured by Hitachi High-Tech Co., Ltd.), the transmittance in the wavelength range of 1800 to 2200 nm is continuously measured by the double beam direct ratio metering method, and each transmittance value (T _IR i for each wavelength of 1 nm) is measured. ) The percentage of the value obtained by dividing the total of T _IR i by the number of measurement points (n) was defined as the light transmittance T _IR (%) at a wavelength of 1800 to 2200 nm. Further, the light transmittance T _IR (%) is sometimes referred to as near-infrared transmittance because of its property, and is commonly used in the case of implementation. In addition, as shown in Table 1, they are listed in a relationship inversely proportional to the heat ray blocking efficiency described later.

(3) YI value (yellowness)
Using a spectrocolorimeter CM-5 (manufactured by Konica Minolta Co., Ltd.), determine the L ^* value, a ^* value, and b ^* value according to JIS-K7105 with a D65 light source 2 ° field of view, and calculate the YI value according to JIS-K7373. did.

(4) Light transmittance (%) at a wavelength of 200 to 380 nm
Using a spectrophotometer U-2001 (manufactured by Hitachi High-Tech Co., Ltd.), the transmittance in the wavelength range of 200 to 380 nm is continuously measured by the double beam direct ratio photometry, and the transmittance value T _UV i for each wavelength of 1 nm is obtained. Obtained. The total of T _UV i was divided by the number of measurement points (n) to obtain the light transmittance T _UV (%) at a wavelength of 200 to 380 nm. From the viewpoint that 10-year deterioration due to ultraviolet rays is less than 20%, 50% or less is preferable. In addition, because of its nature, it is sometimes referred to as ultraviolet transmittance, and it is commonly used in the implementation. (5) Haze (%)
According to JIS K7105-1981, it measured using the haze meter (Suga Test Instruments Co., Ltd. product HGM-2DP (for C light)). Considering visibility of about 30 meters ahead of the film, 25% or less is preferable.

(6) Heat ray blocking efficiency (%)
Heat ray blocking evaluation with a cubic black box composed of a black panel with a side of 30 cm, a 100 W incandescent lamp at the center of the box, a temperature measuring sensor (temperature measuring element) at the center of the bottom, and a film holder at the middle height The heat ray blocking efficiency was calculated using a testing machine (FIG. 1).
Install the above tester in a room temperature-controlled at 23 ° C, place the measurement film horizontally on the film holder in the black box, and detect the bottom temperature Ti (° C) 20 minutes after incandescent lamp irradiation with a temperature sensor. Recorded. The ratio of the temperature difference from the bottom temperature Tb (° C.) 20 minutes after the incandescent lamp irradiation when no film was set was compared as the heat ray blocking efficiency. It is preferable that the heat ray blocking efficiency is 20% or more on the basis that the human body can feel a temperature difference immediately through the film.
Heat ray blocking efficiency (%) = 100 × (Tb-Ti) / (Tb-23).

(7) Particle size The particle size of ITO and blue pigment was determined by cutting a fluororesin film containing particles into ultrathin sections having a thickness of 0.1 μm or less perpendicular to the film surface, and using a transmission electron microscope (for example, JEOL Ltd.) ) JEM-1200EX, etc.) is used and observed at a measurement magnification of 200,000 times or more, and the diameter is measured as the major axis at the position where the diameter of approximately 50 individual particles is the longest in the observed visual field. Was defined as the average particle size.

(8) Weather resistance test Using a sunshine weather meter manufactured by Suga Test Instruments Co., Ltd., an accelerated exposure test was conducted in accordance with JIS K7363, and various film transmittances, hazes and heat ray shielding evaluations after 500 hours of the test were conducted. .

(A) Production of ITO-dispersed fluororesin (ITO master) Indium tin oxide (ITO) powder having an average particle diameter of 30 nm and pre-pulverized ethylene / tetrafluoroethylene copolymer ("Neofluon" manufactured by Daikin Industries, Ltd.) A mixture of (registered trademark) “ETFE EP-526) was melt-kneaded with a Banbury mixer to obtain a composition containing 20% by weight of ITO. Subsequently, this composition and an ethylene-tetrafluoroethylene copolymer ("Neofluon (registered trademark)" ETFE EP-546, manufactured by Daikin Industries, Ltd.) pellets (ETFE pellets) so that indium tin oxide is 5% by weight. The mixture was fed to a bent twin screw extruder, extruded into a strand shape and cut to produce a pellet-like ITO-containing ETFE resin (ITO master A1).

(B) Production of blue pigment-dispersed fluororesin (blue master) Cobalt blue having an average particle diameter of 50 nm (manufactured by Dainichi Seika Kogyo Co., Ltd., FCM H1104) and a pre-powdered ethylene / tetrafluoroethylene copolymer ( A mixture of “Neofluon (registered trademark) ETFE EP-526” manufactured by Daikin Industries, Ltd. was melt kneaded with a Banbury mixer to obtain a composition containing 20% by weight of cobalt blue. Next, this composition and ETFE pellets were mixed so that the cobalt blue would be 2% by weight, supplied to a vent type twin screw extruder, extruded into a strand shape, cut, and pelletized cobalt blue-containing ETFE resin (blue master). B1) was produced.

[Example 1]
ETFE pellets: 462.5 kg, ITO master A 1: 25 kg, and blue master B 1: 12.5 kg are uniformly mixed, supplied to a single screw extruder with a screw diameter of 65 mm, filtered through a filter, and then T-die at 330 ° C. The film is extruded into a film and brought into contact with a cooling roll set at 175 ° C., cooled, solidified, and wound, so that the ITO content of 100 μm thickness is 0.25 wt% and the cobalt blue content is 0.050 wt%. An unstretched film was obtained.
The obtained film had no yellowness, was colorless and transparent, and had good transparency so that the outdoor scenery through the film looked natural. The near-infrared transmittance of this film was as low as 38.7%, and the heat ray blocking efficiency by a heat ray blocking evaluation tester was 34.5%. The film had a UV transmittance of 26.5% and had a UV blocking effect. The film properties are summarized in Table 1.

[Example 2]
Using the same raw materials used in Example 1, ETFE pellets: 485 kg, ITO master A 1:10 kg, and blue master B 1: 5 kg are uniformly mixed, and a single-screw extruder with 65 mm screw diameter, filter, T die The film was supplied to a film forming apparatus equipped with a cooling drum, and an unstretched film having an ITO content of 250 μm in thickness of 0.10 wt% and a cobalt blue content of 0.020 wt% was obtained by melt extrusion film forming.
The obtained film had no yellowness, was colorless and transparent, and had good transparency so that the outdoor scenery through the film looked almost natural. The near-infrared transmittance of this film was as low as 42.3%, and the heat ray blocking efficiency in the heat ray blocking evaluation tester was 36.1%. The film had a UV transmittance significantly reduced to 6.1%, and also had a UV blocking effect. The film properties are summarized in Table 1. Moreover, the visible light transmittance after the weather resistance test is 90.2%, the near-infrared transmittance is 43.0%, the ultraviolet transmittance is 6.3%, and the YI is 4.3. It was a film with high weather resistance. The film properties after the weather resistance test are summarized in Table 2.

[Examples 3 and 4, Comparative Examples 1 and 2]
An unstretched film having a thickness of 250 μm was obtained in the same manner as in Example 2 except that the blending amount of the ITO master was variously changed.
The film properties are summarized in Table 1. As the ITO content in the film increases, the average light transmittance at 1800 to 2200 nm decreases, and the heat ray blocking efficiency increases in inverse proportion. When the ITO content was 0.003% by weight (Comparative Example 1), the near-infrared transmittance was as high as 92.4%, and the heat ray blocking efficiency was insufficient at 7.2%. With an ITO content of 0.30% by weight (Comparative Example 2), it can be said that there is a heat ray blocking effect in this case, but the haze was as high as 27.0% and the transparency was insufficient.

[Examples 5 and 6, Comparative Examples 3 and 4]
An unstretched film having a thickness of 50 μm was obtained in the same manner as in Example 2 except that the blending amount of the ITO master was variously changed. The film properties are summarized in Table 1. As the ITO content in the film increases, the near-infrared transmittance decreases and the heat ray blocking efficiency improves. When the ITO content was 0.10% by weight (Comparative Example 3), the near-infrared transmittance was as high as 68.6%, and the heat ray blocking efficiency was 12.9%, which was insufficient. When the ITO content was 2.00% by weight (Comparative Example 4), the heat ray blocking efficiency was 45.3% and the heat ray blocking efficiency was effective, but the haze was as high as 71.2% and the transparency was insufficient.

[Examples 7 and 8, Comparative Examples 5 and 6]
An unstretched film having a thickness of 250 μm was obtained in the same manner as in Example 2 except that the blending amount of the blue master was variously changed. The film properties are summarized in Table 1. As the blue content in the film increases, the YI value (yellowness) decreases and becomes colorless, but when the content is excessive, it becomes blue (Comparative Example 6), so there is an optimal content according to the ITO content. It is shown that.

[Example 9, Comparative Examples 7 and 8]
Similar to Example 1 except that ITO masters A2 (average particle diameter 150 nm), A3 (5 nm), and A4 (300 nm) were prepared in the same manner as Example 1 (1) by changing the particle diameter of the ITO master. In addition, an unstretched film having a thickness of 250 μm was obtained. The film properties are summarized in Table 1. When the average particle diameter of ITO was 5 nm, the near-infrared transmittance was as high as 81.6%, and the heat ray blocking efficiency was insufficient at 12.7%. When the average particle size was 300 nm, the near-infrared transmittance was 57.4% and the heat ray blocking efficiency was 26.5%, but the haze was 33.5% and the transparency was insufficient.

[Example 10, Comparative Examples 9, 10]
Similar to Example 1 except that blue master B2 (average particle diameter 100 nm), B3 (5 nm) and B4 (250 nm) were prepared in the same manner as in Example 1 (2) by changing the particle diameter of the blue pigment. In addition, an unstretched film having a thickness of 250 μm was obtained. The film properties are summarized in Table 1. When the average particle size of the blue pigment was 5 nm, the near-infrared transmittance was as high as 69.8%, and the heat ray blocking efficiency was insufficient at 16.4%. When the average particle size was 250 nm, the near-infrared transmittance was 41.9% and the heat ray blocking efficiency was 37.2%, but the haze was as high as 28.2% and the transparency was insufficient.

[Example 11]
Copper phthalocyanine having an average particle size of 50 nm (manufactured by Dainichi Seika Kogyo Co., Ltd. and pre-pulverized ethylene / tetrafluoroethylene copolymer (“Neofluon (registered trademark)” ETFE EP-526 manufactured by Daikin Industries, Ltd.)) The mixture was melt kneaded with a Banbury mixer to obtain a composition containing 20% by weight of copper phthalocyanine, and this composition was mixed with ETFE pellets so that the copper phthalocyanine was 2% by weight, followed by vent type twin screw extrusion. A non-stretched film having a thickness of 250 μm was obtained in the same manner as in Example 2 except that it was fed into a machine, extruded into a strand, and cut to produce a pellet-like copper phthalocyanine-containing ETFE resin (blue master B5). The resulting film has little yellowness, is colorless and transparent, and has a good transparency that allows the outdoor scenery through the film to look almost natural. The near-infrared transmittance of this film was as low as 44.6%, the heat ray blocking efficiency in the heat ray blocking evaluation tester was 35.7%, and the ultraviolet transmittance was greatly reduced to 6.7%. The film characteristics are summarized in Table 1. The visible light transmittance after a 500 hour weather resistance test was slightly reduced to 85.5%, but the near infrared transmittance was low. Is 45.0%, the heat ray blocking efficiency is 35.8%, the ultraviolet transmittance is 8.3%, and the YI value (yellowness) is 7.3, which is almost the same as the initial value. The film characteristics before and after the weather resistance test are summarized in Table 2.

[Examples 12 to 14]
Similar to Example 2, except that the weight ratio (In / Sn) of indium oxide and tin oxide contained in ITO was changed to produce an ITO master as in Example 1 (1), a thickness of 250 μm. A stretched film was obtained. The film properties are summarized in Table 1. In the range of 3 to 20% by weight of tin oxide in ITO, the heat ray blocking effect is exhibited. In this range, the amount of near-infrared transmittance increases as the tin oxide in ITO decreases, that is, the film improves heat ray blocking efficiency. It was.

[Comparative Example 11]
Extruded into a film in the same manner as in Example 1 (3) using only ETFE pellets without ITO and blue pigment, to obtain an unstretched film having a thickness of 250 μm. The film properties are summarized in Table 1. Since it did not contain other particles that block transmitted light, it was a film showing the highest visible light transmittance and near infrared transmittance in the table. Therefore, the heat ray blocking efficiency shows the lowest value.

[Comparative Example 12]
Instead of containing ITO and blue pigment, antimony tin compound (ATO) fine particles shown in Table 1 were mastered in the same manner as in Example 1 (1). Further, it was extruded to form a film in the same manner as in Example 1 (3) to obtain a 250 μm unstretched film. Although it shows a heat ray blocking effect as compared with Comparative Example 11, for example, compared with Example 4, the ATO content is 4 times greater than the ITO content, but the heat ray blocking efficiency was about 1/4 times. . ATO was a film having a very low effect on the content of particles compared with ITO.

  The fluororesin film of the present invention is excellent in transparency, heat ray blocking properties, and weather resistance, and is a fluororesin molded product widely used for building roofing materials, wall materials, window materials, arcades, ceiling domes, carports, etc. In particular, it is possible to amplify the utility value in that it has a heat ray blocking effect with good visible light transmittance and a heat ray blocking efficiency exceeding 20%.

1 Black Box 2 Infrared Lamp 3 Temperature Sensor 4 Film Holder 5 Measurement Film 6 Temperature Recorder

Claims (4)

A fluororesin film containing indium tin oxide having an average particle diameter of 10 to 200 nm and a blue pigment having an average particle diameter of 10 to 200 nm, the content A (wt%) of indium tin oxide and the content B of blue pigment (% By weight) satisfies the following formulas (1) and (2) simultaneously with a film thickness of t (μm).
10 / t ≦ A ≦ 60 / t (1)
0.05A ≦ B ≦ 0.3A (2) Furthermore, the fluorine resin film according to claim 1 which satisfies the following formula (A) as a light transmittance _T IR (%) at a wavelength 1800～2200Nm.
20 ≦ T _IR ≦ 70 (A) The film thickness t of the fluororesin film is 10 to 500 μm, the yellowness YI of the fluororesin film, the light transmittance T _V (%) at a wavelength of 380 to 700 nm, and the light transmittance T at a wavelength of 1800 to 2200 nm. The fluororesin film according to claim 1 or 2, wherein _IR (%) satisfies the following formulas (3), (4), and (5) simultaneously.
−0.01t ≦ YI ≦ 0.03t (3)
85 ≦ T _V ≦ 98 (4)
20 ≦ T _IR ≦ 50 (5) The fluororesin film according to any one of claims 1 to 3, wherein the blue pigment is cobalt blue.

Images